Starting a standby database tips Oracle Database Tips by Donald BurlesonDecember 3, 2015

Implementing Standby Databases

Starting the Data Guard Standby Database

The primary database must then be restarted for the new parameters to take effect, or alternatively issue the alter system statements on the primary database to enable the new archive log parameters. Connect as SYSDBA and execute the following statements:

ALTER SYSTEM SET LOG_ARCHIVE_DEST_2="SERVICE=STDBY2";

ALTER SYSTEM SET LOG_ARCHIVE_DEST_STATE_2 = ENABLE;

Then, start the Oracle instance in managed recovery mode using the following commands:

STARTUP NOMOUNT;
ALTER DATABASE MOUNT STANDBY DATABASE;
ALTER DATABASE RECOVER MANAGED Oracle instance DISCONNECT FROM SESSION;

To verify the standby database, check the alert log file for the standby and the primary database. The details about the alert log files and other methods of verification are the same as provided in the section called "On a Remote Host Machine".

Accommodating the Difference in Directory Structure between the Primary and Standby Sites

It may not always be possible to configure two host machines to have the same directory structure. If a standby database is being created and the directory structure on the primary host is different from that on the standby host, the db_file_name_convert and log-file_name_convert parameters on the standby site will have to be set to accommodate the change in directory structure.

Accommodating the Difference in Directory Structure between the Primary and Standby Sites

The process of creating and starting the Oracle instance remains largely the same as explained in the previous two sections. Also, review the dump destinations in the initialization file to make sure that these directories exist on the standby host.

WARNING - Beware that all the difference in directory structure between the primary and standby site may not be accommodated by these two parameters. The ALTER DATABASE RENAME FILENAME statement may have to be used to reflect the filename changes in the control file.

It may not always be possible to have the same directory structure between the primary and the standby host, but in most cases the same directory structure can be simulated using soft links. Keeping the same directory structure eases the management and administration of the standby database, and scripts from the script library can be used without any modification, even if the scripts rely on directory structure.